This invention relates to a ceramics made of preceramic paper or board structures, a method of producing such ceramics and the use thereof.
In the art, porous ceramic articles are used for numerous applications, for instance heat-insulating structures, kiln furniture, porous burner substrates and fire protection structures. Another application is in the field of catalyst supports.
It is known already to dip articles of corrugated board or other paper structures into a slip of metallic or ceramic powders, whereby an external coating is effected (H. Sieber, T. Fey, D. Schwarze, M. Weidner and M. Kresch: “Herstellung von porösen Keramiken aus Papierstrukturen”, in “Das Keramikjahrbuch 2002”, editor: H. Reh, Göller Verlag, Baden-Baden/Germany, pp. 47-54 (2003)). The correspondingly dipped papers then are subjected to pyrolysis in inert gas and to a subsequent temperature treatment in air at 1400° C. With this procedure, high-temperature resistant, cellular ceramics of comparatively low weight are obtained already. It is a disadvantage of the prior art method that on the one hand the coating to be performed is comparatively expensive. Furthermore, coating with the reactive substances is not possible inside the paper structure. Moreover, coating only is possible with articles that can be dipped. However, this excludes any kind of hollow articles, into which the slip cannot penetrate. Furthermore, when coating fine structures, such as a fine flute in the corrugated board, a uniform coating of the surface by dipping into the slip no longer is ensured.